You can put hand sanitizer on your armpits although it's not recommended.
Hand sanitizer contains alcohol that can irritate and dry out the skin and may cause a burning sensation or rash in your armpits.
While the hand sanitizer can kill bacteria on your armpits it can also kill beneficial bacteria on the skin and armpits that help to control odor.
You should use normal soap and water to wash and clean your armpits and then put some deodorant on your armpits instead.
Your armpits are sensitive areas and hand sanitizer should not be put on any sensitive areas of your body including your armpits.
Hand sanitizer should also not be put near your eyes, in your private area, vaginal area etc.
To clean your armpits and other sensitive areas you can also use antibacterial soap or a mixture of water and baking soda to help neutralize odor without causing irritation to the skin.
For effective odor control of your armpits, it's best to use products specifically formulated as deodorants or antiperspirants.
While hand sanitizer may have a mild antibacterial effect, it is not a suitable substitute for traditional deodorants.
To disinfect your armpits and keep them smelling good you should shower daily and wash your armpits really well.
And if you tend to have strong underarm smells, you can use some germicidal soaps that help kill bacteria in your armpits.
Also consider shaving your armpits as this helps to limit the production of sweat which can lead to armpit odor.